Mossbauer and magnetic susceptibility studies on the alloy series FeAl_1-xCr_x

Abstract

Magnetic susceptibility measurements on the alloy series FeAl1-xCrx (0.05<or=x<or=0.60) indicate transitions between paramagnetic and spin glass phases for x=0.35,x=0.40 and between paramagnetic and ferromagnetic phases for x=0.50. Mossbauer experiments show the presence of static magnetic hyperfine interactions for alloys with x>or=0.35. The Mossbauer spectra illustrate the spread of electron density and hyperfine magnetic field at the iron sites. The onset of the ferromagnetic phase is explained in terms of the growth of nearest neighbour iron clusters and the critical concentration found for this alloy series 0.4<x<0.5 is compared with those observed for the analogous series FeAl1-xCux and FeAl1-xFex.

Mössbauer studies of the alloys Fe3Ga4, (Fe1-xTix)3Ga4and (Fe1-yCry)3Ga4

“…A variety of experimental techniques have been used and several theoretical models have been presented to explain the magnetic interactions involved [4,5]. In the ternary alloys FeAl 1−x T x and (Fe 1−x T x ) 3 Ga 4 (T = transition metal) different transition metals T give rise to different degrees of competing ferromagnetic and antiferromagnetic interactions [3,6,7] leading to phenomena such as spin glass phases and reentrant ferromagnetism [3]. A general comprehensive theory on the nature, origin and mechanisms of the magnetic interactions in these alloys has not yet been worked out and further experimental results are valuable to prompt the development of improved theoretical approaches.…”